Measure out 1 cup of water, ¼ cup of peas, and ¼
tsp. of salt. Stir until salt is dissolved. Leave the peas in water
until softened. (I would soak the peas overnight to soften them.)

Put the peas and the salt water in the blender and chop for just
a couple seconds. You may use a fork to squash the peas. The mixture
should be lumpy, containing small pieces of peas. Too much blending
will break up the DNA and make it too hard to see.

Gently mix the peas and water from the blender with a few drops
of soap in a new container.

Step 2.

Put the pea mixture in the strainer.

Filter about 1/3 cup of the liquid into a small glass container.

Wet the end of a toothpick and dip it into the meat tenderizer.

Put the end with the enzymes in the cell mixture and gently stir.

Step 3.

Slowly pour in an equal amount of alcohol (about 1/3 cup)

The alcohol will form a layer on top of the cell debris.

Watch carefully as the DNA precipitates through the alcohol. The
DNA is clear. Small bubbles will attach to the strands as they migrate
up through the alcohol. Use the toothpick to gently stir the alcohol
layer. Notice how those strands move like snot. The snotty substance is
the DNA.

Performance Assessment:

Now that you have extracted DNA from peas, think about each step of
the procedure and
why it works.

How did each of the ingredients in the demonstration help extract
DNA from the
other parts of the cell?

What part of cells would be most affected by soap?

What is it in meat tenderizer that breaks down meat?

Alcohol and salt: Why does only the DNA, and not the other parts of
the cell, rise to
the top after addition of alcohol?

References:

DNA Extraction with Kitchen Chemistry. The Natural History of
Genes. University
of Utah, Salt Lake City, UT